Misfires like a bitch! WOO HOO I'VE FIXED IT!!

[Fraggle]

Gone through everything and discovered a wet number 1 plug. It looks like fuel rather than oil though.

Checked valve clearances, replaced plugs, leads, cap, points, rotor, drained fuel tank, but still plug getting wet.

Any ideas?

Could it be a valve prob, if so what do I need to do / check?

I will be stripping carbs (ICT's) down for a good clean but doubt that's it as they are pretty new and numer 2 plug looks fine, but all the same will strip them.

Any help much appreciated,

Thanks 8)

 

[pete nice]

If you suspect a moody valve, now you have set the clearances, (double check that cylinder unless you are 100% sure it's right) do a quick compression test, this will give you a good insight to what is going on.

Does the rest of the engine run ok, or is it sick all over.

Condenser & coil might be worth a try too.

There is always the possibility of moody petrol. You can run a pipe straight to a Jerry can to prove this out, but is unlikely, it does happen but very rare.

Check for air leaks too.

 

[Fraggle]

Hi Folks

Here's what I've discovered so far.....

Did a compression test and all fine 120 on 12&3 115 on 4.

Stripped cleaned and reassembeld carbs plus tuned, balanced etc

New dizzy, points, condenser, rotor etc

I definately have a big fat spark at the plug as tested it by grounding to the case. I also swapped my dizzy as the cam lobes were worn on the old one giving differing points gaps.

I think that having had the spark plugs out and carbs off helped the cyllinder to 'dry out' a bit thus when I started it I thought I'd sorted my probs as was running ok.......then after about 4 mins I revved up to 4K and then it died off again and is basically running only on 3 cyllinders again. I pulled off the lead and nothing changed.

I think the head might be cracked or the piston rings are letting oil past them, hence the wet plug (which has oil on it not fuel as I first thought). I think the oil is basically drowing the spark on number 1 cyllinder.

What'd ya recon folks???? Anything else I'm missing? Had similar probs?

Any tips / help much appreciated...ta

 

[Fraggle]

Turns out it was a my CB breather tower which was totally blocked up as was the 90degree bend fitting that I was venting through.

This was causing exessive crank case pressure and forcing oil into the head.

I've gone for much larger straight exit pipe fitting and cleaned it all up.

Well pleased!